Mobile computing devices, such as cellular phones, smart phones and tablets, typically have display screens that are relatively small compared to desktop monitors. For example, a typical smart phone may have a touch screen with about 6 square inches of viewing surface, compared to about 175 square inches for a typical 19 inch (diagonal) monitor. The limited viewing space on a mobile device's display screen can sometimes make it difficult to see small details on the graphical user interface (GUI), or to review photos and share screen information with others.
Handheld light projection-based projection devices have shown promise in enlarging the output area of a mobile application, particularly because they offer the advantage of being able to leverage nearly any physical surface for output projection. However, handheld light projection-based interaction presents several issues for mobile users. For example, since few mobile phones are currently equipped with an embedded projector, the projection-based interaction may require additional hardware, such as a dedicated light projector. Furthermore, in order for a user to interact with a projected user interface (for example, to select items, or provide input via the projected user interface), additional sensors (e.g., a depth camera) may be required for detecting user input in the physical space. Another issue associated with a physical handheld light projector is that a user may encounter significant problems with image stability and/or user fatigue while holding the projector, and a mounting or stabilizing platform may be necessary for holding the projector in a stationary position to project a stationary image.